Optimization of Circular Ring Microstrip Antenna Using Genetic Algorithm

Circular ring microstrip antennas have several interesting properties that make it attractive in wireless applications. Although several analysis techniques such as cavity model, generalized transmission line model, Fourier-Hankel transform domain and the method of matched asymptotic expansion have been studied by researchers, there is no efficient design tool that has been incorporated with a suitable optimization algorithm. In this paper, the cavity model analysis along with the genetic optimization algorithm is presented for the design of circular ring microstrip antennas. The method studied here is based on the well-known cavity model and the optimization of the dimensions and feed point location of the circular ring antenna is performed via the genetic optimization algorithm, to achieve an acceptable antenna operation around a desired resonance frequency. The antennas designed by this efficient design procedure were realized experimentally, and the results are compared. In addition, these results are also compared to the results obtained by the commercial electromagnetic simulation tool, the FEM based software, HFSS by ANSOFT.     

Generalized <Emphasis Type="Italic">N</Emphasis>-coupled maps with invariant measure in Bose-Mesner algebra perspective

By choosing a dynamical system with d different couplings, one can rearrange a system based on the graph with a given vertex dependent on the dynamical system elements. The relation between the dynamical elements (coupling) is replaced by a relation between the vertexes. Based on the E ₀ transverse projection operator, we addressed synchronization problem of an array of the linearly coupled map lattices of identical discrete time systems. The synchronization rate is determined by the second largest eigenvalue of the transition probability matrix. Algebraic properties of the Bose-Mesner algebra with an associated scheme with definite spectrum has been used in order to study the stability of the coupled map lattice. Associated schemes play a key role and may lead to analytical methods in studying the stability of the dynamical systems. The relation between the coupling parameters and the chaotic region is presented. It is shown that the feasible region is analytically determined by the number of couplings (i.e. by increasing the number of coupled maps, the feasible region is restricted). It is very easy to apply our criteria to the system being studied and they encompass a wide range of coupling schemes including most of the popularly used ones in the literature.      

Excitation pattern of the blue emission in Ge-doped silica

The luminescence of Ge-doped glassy SiO₂ has been investigated at room temperature using a deuterium lamp as the excitation source in the ultraviolet and vacuum ultraviolet energy range. Two emission bands are observed around 3 and 4 eV as the excitation increases from 4.5 to 8 eV. The peak shift and bandwidth broadening of the emission around 3 eV indicate the overlapping of several bands. We carried out a Gaussian best-fit approach of the detected spectra and extracted the excitation spectra of three distinct emission: a 2.9 eV band with two excitation channels at 4.7 and 5.3 eV and no contribution above 6 eV and the well-known composite β-band (3.1 eV). The latter is resolved into two Gaussian components whose excitation spectra present three main excitations around 5.1, 6.5 and 7.3 eV.     

Non-contact spectral analysis of cytochrome c on carbon electrodes with optical waveguide spectroscopy

To realize the spectral analysis of molecules on the opaque substrate, we proposed non-contact optical waveguide (NOW) spectroscopy. The cyt.c was adsorbed on the carbon substrate by dipping method. This was fixed above the optical waveguide. The gap between the carbon substrate and the waveguide was controlled by latex beads with a diameter of 120 nm as a spacer. A clear NOW spectrum based on the adsorbed cyt.c on the carbon substrate was observed. The cyt.c was easily adsorbed on the carbon surface with an oxidized form by the dipping method. The electrochemical cell system constructed on the waveguide enabled the dynamic analysis on the redox reaction of the adsorbed cyt.c on the carbon electrode. The adsorbed cyt.c showed stable redox reaction without the dislocation or re-dissolution in an aqueous solution.     

Swelling and Drying Mechanisms of Freeze-Thawed Polyvinyl Alcohol/Egg White/Montmorillonite Bionanocomposite Hydrogels

Abstract

Polyvinyl alcohol and egg white bionanocomposite hydrogels loaded with montmorillonite clay were fabricated by a freezing-thawing technique. The bionanocomposite hydrogels showed an exfoliated morphology and they had a more interconnected and dense network as compared with the clay-free sample. The montmorillonite layers acted as multifunctional crosslinkers and the bionanocomposite hydrogels had nanoscale, slit-shaped pores. The swelling ratios of the bionanocomposite hydrogels were increased either by decreasing the content of incorporated montmorillonite or by increasing the pH of the swelling medium. It was found that the bionanocomposite hydrogels having a higher content of montmorillonite exhibited a slightly slower drying process with a longer drying duration. Using the Ritger-Peppas model, it was shown that the swelling and drying mechanisms for all bionanocomposite hydrogels were non-Fickian diffusion. According to the Peppas-Sahlin model, it was found that the absorption of the swelling agent molecules during the swelling process and also the removal of water molecules during the drying process in the early stages of the processes occurred mostly due to their diffusion. At higher swelling or drying times, the contribution of the relaxation (for swelling) and shrinkage (for drying) of the polyvinyl alcohol polymeric chains and egg white protein chains was increased.     

Quantum conductance investigation on carbon nanotube–based antibiotic sensor

Journal of Solid State Electrochemistry - Nanostructured carbon material (NSCM) based chemiresistive sensors are popular for sensing different analytes because of their high sensitivity, low cost,...     

Pure annihilation decay of strange beauty meson into two charm heavy mesons

In this study, the heavy to heavy decay of \begin{document}$ B^0_s\rightarrow D^{*+}D^- $\end{document} is evaluated through the factorization approach by using the final state interaction as an effective correction. Under the factorization approach, this decay mode occurs only through the annihilation process, so a small amount is produced. Feynman's rules state that six meson pairs can be assumed for the intermediate states before the final meson pairs are produced. By taking into account the effects of twelve final state interaction diagrams in the calculations, a significant correction is obtained. These effects correct the value of the branching ratio obtained by the pure factorization approach from \begin{document}$ (2.41\pm1.37)\times10^{-5} $\end{document} to \begin{document}$ (8.27\pm2.23)\times10^{-5} $\end{document}. The value obtained for the branching ratio of the \begin{document}$ B^0_s\rightarrow D^{*+}D^- $\end{document} decay is consistent with the experimental results.     

The social responsibility of environmental analysis

A literature updated has been made on the academical studies focused on the social impact of environmental studies, paying attention to both, the quality of the information provided and the side effects of the methodology employed, also considering the importance of the analytical methodologies in the development of remediation processes and the key subject of the transmission of the environmental information to the policy makers and the general society.     

Multiple rogue wave and solitary solutions for the generalized BK equation via Hirota bilinear and SIVP schemes arising in fluid mechanics

The multiple lump solutions method is employed for the purpose of obtaining multiple soliton solutions for the generalized Bogoyavlensky-Konopelchenko(BK) equation. The solutions obtained contain first-order, second-order, and third-order wave solutions. At the critical point,the second-order derivative and Hessian matrix for only one point is investigated, and the lump solution has one maximum value. He's semi-inverse variational principle(SIVP) is also used for the generalized BK equation. Three major cases are studied, based on two different ansatzes using the SIVP. The physical phenomena of the multiple soliton solutions thus obtained are then analyzed and demonstrated in the figures below, using a selection of suitable parameter values.This method should prove extremely useful for further studies of attractive physical phenomena in the fields of heat transfer, fluid dynamics, etc.